600311 Disclosed is a support tray for growing shellfish. The support tray has a number of recesses arranged in a series of parallel rows. The recesses incorporate means adapted to create a mark on the shell of the shellfish as it grows. Each recess has at least one opening to a channel adapted to allow air and water to enter and leave the recess when the support is in use with shellfish growing. Also claimed is a method of growing shellfish.